Plaster-board



. 1. SQHUMACHEH.

PLASTER BOARD. APPLICATION FILED JULY 5. l-9l9.

1,333,579. Patented Mar. 9,1920.

Edges Uieyamfied add al'denai ,bga $12111 or cement glue.

Inventor cfohn flckwnuwhezby 7M X kisji'laz-neyrs UNITED STATES- PATENT.orrioii.

JOHN SQHUMACHER, 0]? LOS ANGELES, CALIFORNIA.

PLASIER-BOARD.

Specification of Letters Patent.

Patented Mar. 9,1920.

. Application filed July 5, 1919. Serial No. 308,765.

for plasterboard is brittle, after it has hare dened, and will break andchip at the edges with rough handling. The finished lengths of plasterboard are set up on end during handling and transportation. During suchhandling the edges are sometimes broken and chipped, the surface sheetsbroken away from the plaster body, and the board otherwise marred at theedges. When the edges of the board become wet due to lack of protectionduring damp weather, or during puttying, the moisture is absorbed by theplaster causing it to swell slightly and the paper sheets to loosen atthe edges.

The principal object of this invention is to provide a plaster boardhaving the exposed edges of the plastic body case-hardened andwaterproofed. Thus, swelling by the absorption of moisture, loosening ofthe paper sheets due to absorption of moisture,

is prevented. V

These objects will be more fully understood. as will also other objectsand corresponding accomplishments of my invention, from the followingdetailed description of a preferred embodiment thereof. For the purposeof this description reference is had to the accompanying drawing, inwhich:

Figure 1 represents in perspective a frag ment of the end of a finishedlength of plaster board; Fig. 2 is a section through the and chipping ofthe edges during'handling plaster board at one end, the view being on anenlarged scale; Fig. 3, is a perspective view of fragments oftwo'lengths of plaster board at a seam or joint, illustrating the seamproduced with my improved plaster board; and Fig. 4 is a View similar toFig. 3

' showing a seam'between lengths of plaster board which are notcase-hardened and have swelled due to the absorption of moisture.

The plaster board shown herein is preferably made of plaster placedbetween sheets of paper which have been treated so as to ferring moreparticularly the covering sheets of paper are indicated by of plasticcomposition ing the edges.

retard permeation by moisture. During the process of manufacture theunits of plaster board are piled in stacks prior to the settingandaretrimmed to the finished length. dimenslons. The board is permitted toset while in the stack, and later further dried by placing in dry kilns.In the process just described I prefer to angle the stacks of units sothat they stand upon their side edges, suitably spaced'apart, in whichposition they are placed in the kiln; During this 1n1t1al' handling,especially when angling the units, the edges may become marred.

The plaster board shown herein has the "general appearance of ordinaryplaster board and the initial steps in the process of manufacturmg arecarried outas usual. Reto the drawing,

5 and 6, and theintermediate body or layer Immediately after the unitshave 'been trimmed, and while in the stack, a sizing or cement glue, forillustration one having the ngredients gelatin glue, alum, and potash.is applied to the exposed edges of the plas tic body. This may be donein any manner found convenient as by spraying or paint However, myinvention is not limited to the application of theglue while the boardis soft. The application may be made at any time. Sufiicient glue shouldbe pregnate the plastic body, forming when dry case-hardened'edges. Suchan edge is indicated by 8 in-Figs. 2 and 3. When thoroughly dry theplastic body, atthe edges hardened and water-proof. The edges are thusreinforced and molsture reslstant.

Referring to Fig. 4, lengths of plaster board-A and B having untreatededgesare :joined by a plaster putty C. This putty is moist when applied,and the moisture therefrom w1ll permeate the edges of the plaster boardlengths at the seam. This results in applied'so that the latterwillimwhere it has been impregnated, will be case treated according to myinvention. The plaster putty F- dries'and hardens without the moisturepermeating the edges of the plaster board lengths at the seams, the gluepreventing the same. Thus, a smooth wall is secured.- Q

In the foregoing description, I have de- I scribed my product as formedby using paper which retards permeation of moisture. However, theinvention is not limited to plaster board formed by this process.

What I claim is: i 1. A plasterboard comprising a. plastic body havingits edges impregnated with a reinforcing and Waterproofing substance.

2. A plaster board comprising a body of plastic material disposedbetween fibrous I covering sheets adhering thereto, the exposed edges ofsaid body being impregnated With a case-hardening and Waterproofingsubstance.

3. Aplaster-board comprising a body of plastic material, and top andbottom paper covering sheets adhering thereto, the ex- 5. A plasterboard comprising a body of plastic material and top and bottom papercovering sheets "adhering thereto, the exposed edges of said body beingimpregnated with a reinforcing substance.

r 6. A plasterboard comprising a body of plastic material disposed,between fibrous covering sheets adhering thereto, the exposed edges, ofsaid body having a reinforc-' ing and-waterproofing substance )appliedthereto.f

In witness that -I claim the foregoing I have hereunto subscribed myname this 26th day of June, 191-9.

JOHN SOHUMACHER'.

